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homogenous symbols

marysmita

Hi,

I am using Homogenous -'parts per package' symbol on my design. i get a netlisting error if i dont connect the power pins present on all the parts. ( for eg. for a HEX inverter IC with 6 parts, the power (#14) & GND (#7) pins are present on all the parts. ) is there a way to avoid connecting on all parts and successfully complete netlisting. 

PS: I am not keen to create Hetrogenous Parts as that would require a lot of modification in my symbol library. 

Thanks in advance for all your suggestions. 

  • oldmouldy
    No, you need to connect all the power pins consistently to get the design to work. Capture will check the the power connections are consistent as part of the design integrity checking. IF you have any unconnected Power pins, they will connect to a Global Net name os the same name as the Pin, if this not the name of the required Power net, the sections of the part cannot be packaged together.
  • marysmita
    But if I create the part as Hetrogenous, I dont need to show the power and ground pin on all the parts. If I am not planning to use Back annotation, it is advisable that I create a hetrogenous part per package symbol for the regular Logic gates ( hex inverter or quad AND Gate)?
  • oldmouldy

    Yes, that's true. A Homogeneous part has the same graphics and pins in all sections, that means the you will have multiple power pins and they, in turn, must be consistently connected to get the part packaged properly. A Heterogeneous part can have different graphics and pins in each section, such as having the power pins in one section, and not in others, or having the power pins in a section on their own.

    Back annotation, or not, doesn't really come into it. You can have Homogeneous, or Heterogeneous, parts as required for design convenience. Homogeneous parts are a little more simple since the graphics are only created once for all the sections but the power pins need to be take care of between the sections in the schematic. Heterogeneous parts allow more flexibility with graphics and pins but need a bit more effort to create, Equally, some parts. like large processors and FPGAs, "pretty much" have to be designed as Heterogeneous parts.

  • marysmita

    Thanks for your quick response.

    regards,

    Mary

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